Fall colors could peak early in Wisconsin this year

A wet summer has led to some leaves changing colors earlier than in past years, and an online map predicts colors might peak as early as the third week in September.
Chelsey Lewis

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A canopy of colorful leaves decorate the trees near The Basilica of the National Shrine of Mary, Help of Christians, at Holy Hill in Hubertus in October 2015.(Photo: Mike De Sisti / Milwaukee Journal Sentinel)Buy Photo

Get your Instagram filters ready and plan your Holy Hill visits: Fall colors could be coming early to Wisconsin this year.

Leaves have already started to change in northern Wisconsin and could reach their peak there as early as the third week in September, according to a Fall Foliage Prediction Map from SmokyMountains.com. That's about a week earlier than they normally peak in that part of the state.

The local booking website's interactive map predicts when fall colors will peak in every county in the country, based on several million data points including NOAA historical and forecast weather, when leaves have peaked in the past and current observations.

According to the map, colors should peak in southern Wisconsin around Oct. 1. They don't usually peak in that part of the state until mid- or late-October.

"Due to the heavier precipitation throughout the summer months, this year's leaf model is predicting an earlier-than-typical peak fall," said Wes Melton, the map's creator. "However, the NOAA 90-day future precipitation and temperature graphs point to a prolonged color period for much of the country."

Travel Wisconsin maintains its own foliage map, the Fall Color Report, which shows what colors are currently like across the state and when they're expected to peak.

The main factor that causes leaves to turn is shorter days, and that doesn't change year to year, of course. As daylight decreases, leaves stop producing chlorophyll, allowing their true colors — orange and yellow, caused by carotenoid pigments that are always in the leaves — to shine through. Red colors come from anthocyanin, which trees produce to protect the leaves and recover nutrients before they fall off.

But weather can also play a role in the changing leaves. A drought can delay the arrival of colors. An early frost or heavy winds can cause them to drop early. According to the Wisconsin Department of Natural Resources, the best recipe for prime fall colors is a warm, wet spring; a summer that's not too hot or dry; and a fall with warm, sunny days and cool, but not freezing, nights.

This year's early changers are not necessarily a good thing, however.

"Our folks have said that the early color that they've seen is due to the water-level stress, so the fact that we've had so much moisture this season," said Kirsten Held, a forestry outreach and education specialist with the DNR. "When a tree is stressed, they also turn color."

Hardwoods in low-lying areas have been turning first, according to Todd Lanigan, a forest health specialist in Eau Claire.

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Fall colors blanket the trees along the North Country Trail in Ashland County.(Photo: Chelsey Lewis/Milwaukee Journal )

"These lowland areas are holding more water this year, and it is affecting the trees. The trees in these areas are stressed from being in water too long, and this is causing the hardwoods leaves to turn color early," Lanigan wrote in a release.

Wisconsin has seen more than its share of rainfall this year. The state saw an average of 25.25 inches of precipitation from January through July — 7.14 inches above average. That's the most ever in the 123 years data has been collected.